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WORKING OF TRANSISTOR AS A SWITCH The process of applying DC voltages across the different terminals of a transistor is called Biasing. For normal operation the emitter-base junction is always forward biased while the collector base junction is reverse biased. Lets look how TRANSISTOR ACT AS A SWITCH The switching action of a bipolar junction transistor can be explained easily with the help of its output characteristics. Transistor mainly works on mainly three regions ACTIVE SATURATION CUTOFF TRANSISTOR IS IN ON CONDITION WHEN IT IS IN SATURATION MODE. And in OFF state when transistor is in CUTOFF REGION. When a transistor is working as a switch,the cutoff and saturation regions are the stable regions of its operation,while active region is the unstable state To make a transistor in off mode, make Vce=Vcc in common emitter configuration, where Vcc is the supply voltage and Vce is the voltage across collector-emitter terminal. Simillarly, to make Transistor ON we have to give or main...

Liquid Crystal Display (LCD) LCD are passive display devices characteristics by very low power consumption and good contrast ratio. The liquid crystal display does not emit light or generate light. It requires an external or internal light source. Although LED give off light but LCD are not light sources but controls light. LCD a reflect part of surround by light. Principle The molecules in ordinary liquids normally have random orientations. In liquid crystals, the molecules are oriented in liquid crystals, the molecules are oriented in a definite crystal pattern when an electric field is applied to these crystals the molecules which are approximately cigar shaped, tend to aligns themselves perpendicular to the field. Charge carriers flowing through the liquid disturb the molecular alignment and cause a turbulence within the liquid, this is illustrated in below fig .                                   ...